1. Field of the Invention
This invention relates to formation of a native oxide on mercury cadmium telluride (Hg.sub.1-x Cd.sub.x Te) semiconductor surfaces and, more particularly, to the formation of a native oxide on such surfaces by ozone oxidation.
2. Description of the Prior Art
In order to fabricate stable, high performance photovoltaic diodes and charge coupled devices (CCDs), certain semiconductor surfaces adjacent insulators require passivation. This passivation is usually accomplished by the growth on the semiconductor surface of a native oxide layer, which has superior chemical and electrical properties compared to surfaces with no native oxide. Complete reaction of all constituent elements of the semiconductor to stable oxidation states is necessary for thermal stability as well as high electrical resistivity. In addition, the bonds between the atoms in this oxide passivation must be strong and complete to prevent residual electric charge or paths for charge conduction. Residual charge can accumulate or invert CCD and diode surfaces, while charge conduction can leak current around diode junctions. Since the native oxide grown for these purposes is usually very thin, it must resist decomposition during the formation of an additional overlying insulator such as ZnS. The passivation process must also be reproducible and reliable.